/*
 * Licensed to the Apache Software Foundation (ASF) under one or more
 * contributor license agreements.  See the NOTICE file distributed with
 * this work for additional information regarding copyright ownership.
 * The ASF licenses this file to You under the Apache License, Version 2.0
 * (the "License"); you may not use this file except in compliance with
 * the License.  You may obtain a copy of the License at
 * 
 *      http://www.apache.org/licenses/LICENSE-2.0
 * 
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package org.apache.catalina.util;

import java.text.MessageFormat;
import java.util.Hashtable;
import java.util.Locale;
import java.util.MissingResourceException;
import java.util.ResourceBundle;
import java.net.URLClassLoader;

/**
 * An internationalization / localization helper class which reduces the bother
 * of handling ResourceBundles and takes care of the common cases of message
 * formating which otherwise require the creation of Object arrays and such.
 * 
 * <p>
 * The StringManager operates on a package basis. One StringManager per package
 * can be created and accessed via the getManager method call.
 * 
 * <p>
 * The StringManager will look for a ResourceBundle named by the package name
 * given plus the suffix of "LocalStrings". In practice, this means that the
 * localized information will be contained in a LocalStrings.properties file
 * located in the package directory of the classpath.
 * 
 * <p>
 * Please see the documentation for java.util.ResourceBundle for more
 * information.
 * 
 * @author James Duncan Davidson [duncan@eng.sun.com]
 * @author James Todd [gonzo@eng.sun.com]
 */

public class StringManager {

	/**
	 * The ResourceBundle for this StringManager.
	 */

	private ResourceBundle bundle;

	private static org.apache.juli.logging.Log log = org.apache.juli.logging.LogFactory
			.getLog(StringManager.class);

	/**
	 * Creates a new StringManager for a given package. This is a private method
	 * and all access to it is arbitrated by the static getManager method call
	 * so that only one StringManager per package will be created.
	 * 
	 * @param packageName
	 *            Name of package to create StringManager for.
	 */

	private StringManager(String packageName) {
		String bundleName = packageName + ".LocalStrings";
		try {
			bundle = ResourceBundle.getBundle(bundleName);
			return;
		} catch (MissingResourceException ex) {
			// Try from the current loader ( that's the case for trusted apps )
			ClassLoader cl = Thread.currentThread().getContextClassLoader();
			if (cl != null) {
				try {
					bundle = ResourceBundle.getBundle(bundleName, Locale
							.getDefault(), cl);
					return;
				} catch (MissingResourceException ex2) {
				}
			}
			if (cl == null)
				cl = this.getClass().getClassLoader();

			if (log.isDebugEnabled())
				log.debug("Can't find resource " + bundleName + " " + cl);
			if (cl instanceof URLClassLoader) {
				if (log.isDebugEnabled())
					log.debug(((URLClassLoader) cl).getURLs());
			}
		}
	}

	/**
	 * Get a string from the underlying resource bundle.
	 * 
	 * @param key
	 *            The resource name
	 */
	public String getString(String key) {
		return MessageFormat.format(getStringInternal(key), (Object[]) null);
	}

	protected String getStringInternal(String key) {
		if (key == null) {
			String msg = "key is null";

			throw new NullPointerException(msg);
		}

		String str = null;

		if (bundle == null)
			return key;
		try {
			str = bundle.getString(key);
		} catch (MissingResourceException mre) {
			str = "Cannot find message associated with key '" + key + "'";
		}

		return str;
	}

	/**
	 * Get a string from the underlying resource bundle and format it with the
	 * given set of arguments.
	 * 
	 * @param key
	 *            The resource name
	 * @param args
	 *            Formatting directives
	 */

	public String getString(String key, Object[] args) {
		String iString = null;
		String value = getStringInternal(key);

		// this check for the runtime exception is some pre 1.1.6
		// VM's don't do an automatic toString() on the passed in
		// objects and barf out

		try {
			// ensure the arguments are not null so pre 1.2 VM's don't barf
			Object nonNullArgs[] = args;
			for (int i = 0; i < args.length; i++) {
				if (args[i] == null) {
					if (nonNullArgs == args)
						nonNullArgs = (Object[]) args.clone();
					nonNullArgs[i] = "null";
				}
			}

			iString = MessageFormat.format(value, nonNullArgs);
		} catch (IllegalArgumentException iae) {
			StringBuffer buf = new StringBuffer();
			buf.append(value);
			for (int i = 0; i < args.length; i++) {
				buf.append(" arg[" + i + "]=" + args[i]);
			}
			iString = buf.toString();
		}
		return iString;
	}

	/**
	 * Get a string from the underlying resource bundle and format it with the
	 * given object argument. This argument can of course be a String object.
	 * 
	 * @param key
	 *            The resource name
	 * @param arg
	 *            Formatting directive
	 */

	public String getString(String key, Object arg) {
		Object[] args = new Object[] { arg };
		return getString(key, args);
	}

	/**
	 * Get a string from the underlying resource bundle and format it with the
	 * given object arguments. These arguments can of course be String objects.
	 * 
	 * @param key
	 *            The resource name
	 * @param arg1
	 *            Formatting directive
	 * @param arg2
	 *            Formatting directive
	 */

	public String getString(String key, Object arg1, Object arg2) {
		Object[] args = new Object[] { arg1, arg2 };
		return getString(key, args);
	}

	/**
	 * Get a string from the underlying resource bundle and format it with the
	 * given object arguments. These arguments can of course be String objects.
	 * 
	 * @param key
	 *            The resource name
	 * @param arg1
	 *            Formatting directive
	 * @param arg2
	 *            Formatting directive
	 * @param arg3
	 *            Formatting directive
	 */

	public String getString(String key, Object arg1, Object arg2, Object arg3) {
		Object[] args = new Object[] { arg1, arg2, arg3 };
		return getString(key, args);
	}

	/**
	 * Get a string from the underlying resource bundle and format it with the
	 * given object arguments. These arguments can of course be String objects.
	 * 
	 * @param key
	 *            The resource name
	 * @param arg1
	 *            Formatting directive
	 * @param arg2
	 *            Formatting directive
	 * @param arg3
	 *            Formatting directive
	 * @param arg4
	 *            Formatting directive
	 */

	public String getString(String key, Object arg1, Object arg2, Object arg3,
			Object arg4) {
		Object[] args = new Object[] { arg1, arg2, arg3, arg4 };
		return getString(key, args);
	}

	// --------------------------------------------------------------
	// STATIC SUPPORT METHODS
	// --------------------------------------------------------------

	private static Hashtable managers = new Hashtable();

	/**
	 * Get the StringManager for a particular package. If a manager for a
	 * package already exists, it will be reused, else a new StringManager will
	 * be created and returned.
	 * 
	 * @param packageName
	 *            The package name
	 */

	public synchronized static StringManager getManager(String packageName) {
		StringManager mgr = (StringManager) managers.get(packageName);

		if (mgr == null) {
			mgr = new StringManager(packageName);
			managers.put(packageName, mgr);
		}
		return mgr;
	}
}
